fs/overlayfs/overlayfs.h

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2 /*
   3  *
   4  * Copyright (C) 2011 Novell Inc.
   5  */
   6
   7 #include <linux/kernel.h>
   8 #include <linux/uuid.h>
   9 #include <linux/fs.h>
  10 #include <linux/namei.h>
  11 #include <linux/posix_acl.h>
  12 #include <linux/posix_acl_xattr.h>
  13 #include "ovl_entry.h"
  14
  15 #undef pr_fmt
  16 #define pr_fmt(fmt) "overlayfs: " fmt
  17
  18 enum ovl_path_type {
  19         __OVL_PATH_UPPER        = (1 << 0),
  20         __OVL_PATH_MERGE        = (1 << 1),
  21         __OVL_PATH_ORIGIN       = (1 << 2),
  22 };
  23
  24 #define OVL_TYPE_UPPER(type)    ((type) & __OVL_PATH_UPPER)
  25 #define OVL_TYPE_MERGE(type)    ((type) & __OVL_PATH_MERGE)
  26 #define OVL_TYPE_ORIGIN(type)   ((type) & __OVL_PATH_ORIGIN)
  27
  28 #define OVL_XATTR_NAMESPACE "overlay."
  29 #define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
  30 #define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
  31
  32 enum ovl_xattr {
  33         OVL_XATTR_OPAQUE,
  34         OVL_XATTR_REDIRECT,
  35         OVL_XATTR_ORIGIN,
  36         OVL_XATTR_IMPURE,
  37         OVL_XATTR_NLINK,
  38         OVL_XATTR_UPPER,
  39         OVL_XATTR_METACOPY,
  40         OVL_XATTR_PROTATTR,
  41 };
  42
  43 enum ovl_inode_flag {
  44         /* Pure upper dir that may contain non pure upper entries */
  45         OVL_IMPURE,
  46         /* Non-merge dir that may contain whiteout entries */
  47         OVL_WHITEOUTS,
  48         OVL_INDEX,
  49         OVL_UPPERDATA,
  50         /* Inode number will remain constant over copy up. */
  51         OVL_CONST_INO,
  52 };
  53
  54 enum ovl_entry_flag {
  55         OVL_E_UPPER_ALIAS,
  56         OVL_E_OPAQUE,
  57         OVL_E_CONNECTED,
  58 };
  59
  60 enum {
  61         OVL_REDIRECT_OFF,       /* "off" mode is never used. In effect  */
  62         OVL_REDIRECT_FOLLOW,    /* ...it translates to either "follow"  */
  63         OVL_REDIRECT_NOFOLLOW,  /* ...or "nofollow".                    */
  64         OVL_REDIRECT_ON,
  65 };
  66
  67 enum {
  68         OVL_XINO_OFF,
  69         OVL_XINO_AUTO,
  70         OVL_XINO_ON,
  71 };
  72
  73 /* The set of options that user requested explicitly via mount options */
  74 struct ovl_opt_set {
  75         bool metacopy;
  76         bool redirect;
  77         bool nfs_export;
  78         bool index;
  79 };
  80
  81 /*
  82  * The tuple (fh,uuid) is a universal unique identifier for a copy up origin,
  83  * where:
  84  * origin.fh    - exported file handle of the lower file
  85  * origin.uuid  - uuid of the lower filesystem
  86  */
  87 #define OVL_FH_VERSION  0
  88 #define OVL_FH_MAGIC    0xfb
  89
  90 /* CPU byte order required for fid decoding:  */
  91 #define OVL_FH_FLAG_BIG_ENDIAN  (1 << 0)
  92 #define OVL_FH_FLAG_ANY_ENDIAN  (1 << 1)
  93 /* Is the real inode encoded in fid an upper inode? */
  94 #define OVL_FH_FLAG_PATH_UPPER  (1 << 2)
  95
  96 #define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \
  97                          OVL_FH_FLAG_PATH_UPPER)
  98
  99 #if defined(__LITTLE_ENDIAN)
 100 #define OVL_FH_FLAG_CPU_ENDIAN 0
 101 #elif defined(__BIG_ENDIAN)
 102 #define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN
 103 #else
 104 #error Endianness not defined
 105 #endif
 106
 107 /* The type used to be returned by overlay exportfs for misaligned fid */
 108 #define OVL_FILEID_V0   0xfb
 109 /* The type returned by overlay exportfs for 32bit aligned fid */
 110 #define OVL_FILEID_V1   0xf8
 111
 112 /* On-disk format for "origin" file handle */
 113 struct ovl_fb {
 114         u8 version;     /* 0 */
 115         u8 magic;       /* 0xfb */
 116         u8 len;         /* size of this header + size of fid */
 117         u8 flags;       /* OVL_FH_FLAG_* */
 118         u8 type;        /* fid_type of fid */
 119         uuid_t uuid;    /* uuid of filesystem */
 120         u32 fid[];      /* file identifier should be 32bit aligned in-memory */
 121 } __packed;
 122
 123 /* In-memory and on-wire format for overlay file handle */
 124 struct ovl_fh {
 125         u8 padding[3];  /* make sure fb.fid is 32bit aligned */
 126         union {
 127                 struct ovl_fb fb;
 128                 DECLARE_FLEX_ARRAY(u8, buf);
 129         };
 130 } __packed;
 131
 132 #define OVL_FH_WIRE_OFFSET      offsetof(struct ovl_fh, fb)
 133 #define OVL_FH_LEN(fh)          (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
 134 #define OVL_FH_FID_OFFSET       (OVL_FH_WIRE_OFFSET + \
 135                                  offsetof(struct ovl_fb, fid))
 136
 137 extern const char *const ovl_xattr_table[][2];
 138 static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
 139 {
 140         return ovl_xattr_table[ox][ofs->config.userxattr];
 141 }
 142
 143 /*
 144  * When changing ownership of an upper object map the intended ownership
 145  * according to the upper layer's idmapping. When an upper mount idmaps files
 146  * that are stored on-disk as owned by id 1001 to id 1000 this means stat on
 147  * this object will report it as being owned by id 1000 when calling stat via
 148  * the upper mount.
 149  * In order to change ownership of an object so stat reports id 1000 when
 150  * called on an idmapped upper mount the value written to disk - i.e., the
 151  * value stored in ia_*id - must 1001. The mount mapping helper will thus take
 152  * care to map 1000 to 1001.
 153  * The mnt idmapping helpers are nops if the upper layer isn't idmapped.
 154  */
 155 static inline int ovl_do_notify_change(struct ovl_fs *ofs,
 156                                        struct dentry *upperdentry,
 157                                        struct iattr *attr)
 158 {
 159         return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL);
 160 }
 161
 162 static inline int ovl_do_rmdir(struct ovl_fs *ofs,
 163                                struct inode *dir, struct dentry *dentry)
 164 {
 165         int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry);
 166
 167         pr_debug("rmdir(%pd2) = %i\n", dentry, err);
 168         return err;
 169 }
 170
 171 static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
 172                                 struct dentry *dentry)
 173 {
 174         int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL);
 175
 176         pr_debug("unlink(%pd2) = %i\n", dentry, err);
 177         return err;
 178 }
 179
 180 static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
 181                               struct inode *dir, struct dentry *new_dentry)
 182 {
 183         int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), dir,
 184                            new_dentry, NULL);
 185
 186         pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err);
 187         return err;
 188 }
 189
 190 static inline int ovl_do_create(struct ovl_fs *ofs,
 191                                 struct inode *dir, struct dentry *dentry,
 192                                 umode_t mode)
 193 {
 194         int err = vfs_create(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, true);
 195
 196         pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
 197         return err;
 198 }
 199
 200 static inline int ovl_do_mkdir(struct ovl_fs *ofs,
 201                                struct inode *dir, struct dentry *dentry,
 202                                umode_t mode)
 203 {
 204         int err = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode);
 205         pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
 206         return err;
 207 }
 208
 209 static inline int ovl_do_mknod(struct ovl_fs *ofs,
 210                                struct inode *dir, struct dentry *dentry,
 211                                umode_t mode, dev_t dev)
 212 {
 213         int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, dev);
 214
 215         pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err);
 216         return err;
 217 }
 218
 219 static inline int ovl_do_symlink(struct ovl_fs *ofs,
 220                                  struct inode *dir, struct dentry *dentry,
 221                                  const char *oldname)
 222 {
 223         int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname);
 224
 225         pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
 226         return err;
 227 }
 228
 229 static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name,
 230                                       void *value, size_t size)
 231 {
 232         int err, len;
 233
 234         WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
 235
 236         err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry,
 237                                name, value, size);
 238         len = (value && err > 0) ? err : 0;
 239
 240         pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
 241                  path->dentry, name, min(len, 48), value, size, err);
 242         return err;
 243 }
 244
 245 static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
 246                                          struct dentry *upperdentry,
 247                                          enum ovl_xattr ox, void *value,
 248                                          size_t size)
 249 {
 250         struct path upperpath = {
 251                 .dentry = upperdentry,
 252                 .mnt = ovl_upper_mnt(ofs),
 253         };
 254
 255         return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
 256 }
 257
 258 static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
 259                                          const struct path *path,
 260                                          enum ovl_xattr ox, void *value,
 261                                          size_t size)
 262 {
 263         return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
 264 }
 265
 266 static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
 267                                   const char *name, const void *value,
 268                                   size_t size, int flags)
 269 {
 270         int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name,
 271                                value, size, flags);
 272
 273         pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
 274                  dentry, name, min((int)size, 48), value, size, flags, err);
 275         return err;
 276 }
 277
 278 static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
 279                                enum ovl_xattr ox, const void *value,
 280                                size_t size)
 281 {
 282         return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
 283 }
 284
 285 static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
 286                                      const char *name)
 287 {
 288         int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name);
 289         pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
 290         return err;
 291 }
 292
 293 static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
 294                                   enum ovl_xattr ox)
 295 {
 296         return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
 297 }
 298
 299 static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry,
 300                                  const char *acl_name, struct posix_acl *acl)
 301 {
 302         return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl);
 303 }
 304
 305 static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry,
 306                                     const char *acl_name)
 307 {
 308         return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name);
 309 }
 310
 311 static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir,
 312                                 struct dentry *olddentry, struct inode *newdir,
 313                                 struct dentry *newdentry, unsigned int flags)
 314 {
 315         int err;
 316         struct renamedata rd = {
 317                 .old_mnt_idmap  = ovl_upper_mnt_idmap(ofs),
 318                 .old_dir        = olddir,
 319                 .old_dentry     = olddentry,
 320                 .new_mnt_idmap  = ovl_upper_mnt_idmap(ofs),
 321                 .new_dir        = newdir,
 322                 .new_dentry     = newdentry,
 323                 .flags          = flags,
 324         };
 325
 326         pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
 327         err = vfs_rename(&rd);
 328         if (err) {
 329                 pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
 330                          olddentry, newdentry, err);
 331         }
 332         return err;
 333 }
 334
 335 static inline int ovl_do_whiteout(struct ovl_fs *ofs,
 336                                   struct inode *dir, struct dentry *dentry)
 337 {
 338         int err = vfs_whiteout(ovl_upper_mnt_idmap(ofs), dir, dentry);
 339         pr_debug("whiteout(%pd2) = %i\n", dentry, err);
 340         return err;
 341 }
 342
 343 static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs,
 344                                           struct dentry *dentry, umode_t mode)
 345 {
 346         struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry };
 347         struct file *file = vfs_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path, mode,
 348                                         O_LARGEFILE | O_WRONLY, current_cred());
 349         int err = PTR_ERR_OR_ZERO(file);
 350
 351         pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
 352         return file;
 353 }
 354
 355 static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
 356                                               const char *name,
 357                                               struct dentry *base, int len)
 358 {
 359         return lookup_one(ovl_upper_mnt_idmap(ofs), name, base, len);
 360 }
 361
 362 static inline bool ovl_open_flags_need_copy_up(int flags)
 363 {
 364         if (!flags)
 365                 return false;
 366
 367         return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
 368 }
 369
 370
 371 /* util.c */
 372 int ovl_want_write(struct dentry *dentry);
 373 void ovl_drop_write(struct dentry *dentry);
 374 struct dentry *ovl_workdir(struct dentry *dentry);
 375 const struct cred *ovl_override_creds(struct super_block *sb);
 376 int ovl_can_decode_fh(struct super_block *sb);
 377 struct dentry *ovl_indexdir(struct super_block *sb);
 378 bool ovl_index_all(struct super_block *sb);
 379 bool ovl_verify_lower(struct super_block *sb);
 380 struct ovl_path *ovl_stack_alloc(unsigned int n);
 381 void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n);
 382 void ovl_stack_put(struct ovl_path *stack, unsigned int n);
 383 void ovl_stack_free(struct ovl_path *stack, unsigned int n);
 384 struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
 385 void ovl_free_entry(struct ovl_entry *oe);
 386 bool ovl_dentry_remote(struct dentry *dentry);
 387 void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry);
 388 void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry,
 389                            struct ovl_entry *oe);
 390 void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
 391                            struct ovl_entry *oe, unsigned int mask);
 392 bool ovl_dentry_weird(struct dentry *dentry);
 393 enum ovl_path_type ovl_path_type(struct dentry *dentry);
 394 void ovl_path_upper(struct dentry *dentry, struct path *path);
 395 void ovl_path_lower(struct dentry *dentry, struct path *path);
 396 void ovl_path_lowerdata(struct dentry *dentry, struct path *path);
 397 struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
 398 enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
 399 enum ovl_path_type ovl_path_realdata(struct dentry *dentry, struct path *path);
 400 struct dentry *ovl_dentry_upper(struct dentry *dentry);
 401 struct dentry *ovl_dentry_lower(struct dentry *dentry);
 402 struct dentry *ovl_dentry_lowerdata(struct dentry *dentry);
 403 int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath);
 404 const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
 405 const struct ovl_layer *ovl_layer_lower(struct dentry *dentry);
 406 struct dentry *ovl_dentry_real(struct dentry *dentry);
 407 struct dentry *ovl_i_dentry_upper(struct inode *inode);
 408 struct inode *ovl_inode_upper(struct inode *inode);
 409 struct inode *ovl_inode_lower(struct inode *inode);
 410 struct inode *ovl_inode_lowerdata(struct inode *inode);
 411 struct inode *ovl_inode_real(struct inode *inode);
 412 struct inode *ovl_inode_realdata(struct inode *inode);
 413 const char *ovl_lowerdata_redirect(struct inode *inode);
 414 struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
 415 void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
 416 void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry);
 417 void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry);
 418 bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry);
 419 bool ovl_dentry_is_opaque(struct dentry *dentry);
 420 bool ovl_dentry_is_whiteout(struct dentry *dentry);
 421 void ovl_dentry_set_opaque(struct dentry *dentry);
 422 bool ovl_dentry_has_upper_alias(struct dentry *dentry);
 423 void ovl_dentry_set_upper_alias(struct dentry *dentry);
 424 bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags);
 425 bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags);
 426 bool ovl_has_upperdata(struct inode *inode);
 427 void ovl_set_upperdata(struct inode *inode);
 428 const char *ovl_dentry_get_redirect(struct dentry *dentry);
 429 void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect);
 430 void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
 431 void ovl_dir_modified(struct dentry *dentry, bool impurity);
 432 u64 ovl_inode_version_get(struct inode *inode);
 433 bool ovl_is_whiteout(struct dentry *dentry);
 434 struct file *ovl_path_open(const struct path *path, int flags);
 435 int ovl_copy_up_start(struct dentry *dentry, int flags);
 436 void ovl_copy_up_end(struct dentry *dentry);
 437 bool ovl_already_copied_up(struct dentry *dentry, int flags);
 438 bool ovl_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
 439                               enum ovl_xattr ox);
 440 bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
 441
 442 static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
 443                                           struct dentry *upperdentry)
 444 {
 445         struct path upperpath = {
 446                 .dentry = upperdentry,
 447                 .mnt = ovl_upper_mnt(ofs),
 448         };
 449         return ovl_path_check_origin_xattr(ofs, &upperpath);
 450 }
 451
 452 int ovl_check_setxattr(struct ovl_fs *ofs, struct dentry *upperdentry,
 453                        enum ovl_xattr ox, const void *value, size_t size,
 454                        int xerr);
 455 int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
 456 bool ovl_inuse_trylock(struct dentry *dentry);
 457 void ovl_inuse_unlock(struct dentry *dentry);
 458 bool ovl_is_inuse(struct dentry *dentry);
 459 bool ovl_need_index(struct dentry *dentry);
 460 int ovl_nlink_start(struct dentry *dentry);
 461 void ovl_nlink_end(struct dentry *dentry);
 462 int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
 463 int ovl_check_metacopy_xattr(struct ovl_fs *ofs, const struct path *path);
 464 bool ovl_is_metacopy_dentry(struct dentry *dentry);
 465 char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding);
 466 int ovl_sync_status(struct ovl_fs *ofs);
 467
 468 static inline void ovl_set_flag(unsigned long flag, struct inode *inode)
 469 {
 470         set_bit(flag, &OVL_I(inode)->flags);
 471 }
 472
 473 static inline void ovl_clear_flag(unsigned long flag, struct inode *inode)
 474 {
 475         clear_bit(flag, &OVL_I(inode)->flags);
 476 }
 477
 478 static inline bool ovl_test_flag(unsigned long flag, struct inode *inode)
 479 {
 480         return test_bit(flag, &OVL_I(inode)->flags);
 481 }
 482
 483 static inline bool ovl_is_impuredir(struct super_block *sb,
 484                                     struct dentry *upperdentry)
 485 {
 486         struct ovl_fs *ofs = OVL_FS(sb);
 487         struct path upperpath = {
 488                 .dentry = upperdentry,
 489                 .mnt = ovl_upper_mnt(ofs),
 490         };
 491
 492         return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE);
 493 }
 494
 495 static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
 496 {
 497         return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW;
 498 }
 499
 500 static inline bool ovl_redirect_dir(struct ovl_fs *ofs)
 501 {
 502         return ofs->config.redirect_mode == OVL_REDIRECT_ON;
 503 }
 504
 505 /*
 506  * With xino=auto, we do best effort to keep all inodes on same st_dev and
 507  * d_ino consistent with st_ino.
 508  * With xino=on, we do the same effort but we warn if we failed.
 509  */
 510 static inline bool ovl_xino_warn(struct ovl_fs *ofs)
 511 {
 512         return ofs->config.xino == OVL_XINO_ON;
 513 }
 514
 515 /*
 516  * To avoid regressions in existing setups with overlay lower offline changes,
 517  * we allow lower changes only if none of the new features are used.
 518  */
 519 static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
 520 {
 521         return (!ofs->config.index && !ofs->config.metacopy &&
 522                 !ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs));
 523 }
 524
 525 /* All layers on same fs? */
 526 static inline bool ovl_same_fs(struct ovl_fs *ofs)
 527 {
 528         return ofs->xino_mode == 0;
 529 }
 530
 531 /* All overlay inodes have same st_dev? */
 532 static inline bool ovl_same_dev(struct ovl_fs *ofs)
 533 {
 534         return ofs->xino_mode >= 0;
 535 }
 536
 537 static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs)
 538 {
 539         return ovl_same_dev(ofs) ? ofs->xino_mode : 0;
 540 }
 541
 542 static inline void ovl_inode_lock(struct inode *inode)
 543 {
 544         mutex_lock(&OVL_I(inode)->lock);
 545 }
 546
 547 static inline int ovl_inode_lock_interruptible(struct inode *inode)
 548 {
 549         return mutex_lock_interruptible(&OVL_I(inode)->lock);
 550 }
 551
 552 static inline void ovl_inode_unlock(struct inode *inode)
 553 {
 554         mutex_unlock(&OVL_I(inode)->lock);
 555 }
 556
 557
 558 /* namei.c */
 559 int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
 560
 561 static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
 562 {
 563         if (fh_len < sizeof(struct ovl_fh))
 564                 return -EINVAL;
 565
 566         return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
 567 }
 568
 569 struct dentry *ovl_decode_real_fh(struct ovl_fs *ofs, struct ovl_fh *fh,
 570                                   struct vfsmount *mnt, bool connected);
 571 int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
 572                         struct dentry *upperdentry, struct ovl_path **stackp);
 573 int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry,
 574                       enum ovl_xattr ox, struct dentry *real, bool is_upper,
 575                       bool set);
 576 struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index,
 577                                bool connected);
 578 int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
 579 int ovl_get_index_name(struct ovl_fs *ofs, struct dentry *origin,
 580                        struct qstr *name);
 581 struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
 582 struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper,
 583                                 struct dentry *origin, bool verify);
 584 int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
 585 int ovl_maybe_lookup_lowerdata(struct dentry *dentry);
 586 struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
 587                           unsigned int flags);
 588 bool ovl_lower_positive(struct dentry *dentry);
 589
 590 static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
 591                                     struct dentry *origin, bool set)
 592 {
 593         return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin,
 594                                  false, set);
 595 }
 596
 597 static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index,
 598                                    struct dentry *upper, bool set)
 599 {
 600         return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set);
 601 }
 602
 603 /* readdir.c */
 604 extern const struct file_operations ovl_dir_operations;
 605 struct file *ovl_dir_real_file(const struct file *file, bool want_upper);
 606 int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
 607 void ovl_cleanup_whiteouts(struct ovl_fs *ofs, struct dentry *upper,
 608                            struct list_head *list);
 609 void ovl_cache_free(struct list_head *list);
 610 void ovl_dir_cache_free(struct inode *inode);
 611 int ovl_check_d_type_supported(const struct path *realpath);
 612 int ovl_workdir_cleanup(struct ovl_fs *ofs, struct inode *dir,
 613                         struct vfsmount *mnt, struct dentry *dentry, int level);
 614 int ovl_indexdir_cleanup(struct ovl_fs *ofs);
 615
 616 /*
 617  * Can we iterate real dir directly?
 618  *
 619  * Non-merge dir may contain whiteouts from a time it was a merge upper, before
 620  * lower dir was removed under it and possibly before it was rotated from upper
 621  * to lower layer.
 622  */
 623 static inline bool ovl_dir_is_real(struct inode *dir)
 624 {
 625         return !ovl_test_flag(OVL_WHITEOUTS, dir);
 626 }
 627
 628 /* inode.c */
 629 int ovl_set_nlink_upper(struct dentry *dentry);
 630 int ovl_set_nlink_lower(struct dentry *dentry);
 631 unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry,
 632                            struct dentry *upperdentry,
 633                            unsigned int fallback);
 634 int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
 635                 struct iattr *attr);
 636 int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
 637                 struct kstat *stat, u32 request_mask, unsigned int flags);
 638 int ovl_permission(struct mnt_idmap *idmap, struct inode *inode,
 639                    int mask);
 640 int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name,
 641                   const void *value, size_t size, int flags);
 642 int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name,
 643                   void *value, size_t size);
 644 ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
 645
 646 #ifdef CONFIG_FS_POSIX_ACL
 647 struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
 648                                  struct inode *inode, int type,
 649                                  bool rcu, bool noperm);
 650 static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type,
 651                                                   bool rcu)
 652 {
 653         return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true);
 654 }
 655 static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap,
 656                                             struct dentry *dentry, int type)
 657 {
 658         return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false);
 659 }
 660 int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
 661                 struct posix_acl *acl, int type);
 662 struct posix_acl *ovl_get_acl_path(const struct path *path,
 663                                    const char *acl_name, bool noperm);
 664 #else
 665 #define ovl_get_inode_acl       NULL
 666 #define ovl_get_acl             NULL
 667 #define ovl_set_acl             NULL
 668 static inline struct posix_acl *ovl_get_acl_path(const struct path *path,
 669                                                  const char *acl_name,
 670                                                  bool noperm)
 671 {
 672         return NULL;
 673 }
 674 #endif
 675
 676 int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags);
 677 bool ovl_is_private_xattr(struct super_block *sb, const char *name);
 678
 679 struct ovl_inode_params {
 680         struct inode *newinode;
 681         struct dentry *upperdentry;
 682         struct ovl_entry *oe;
 683         bool index;
 684         char *redirect;
 685         char *lowerdata_redirect;
 686 };
 687 void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip,
 688                     unsigned long ino, int fsid);
 689 struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev);
 690 struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real,
 691                                bool is_upper);
 692 bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir);
 693 struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir);
 694 struct inode *ovl_get_inode(struct super_block *sb,
 695                             struct ovl_inode_params *oip);
 696 void ovl_copyattr(struct inode *to);
 697
 698 /* vfs inode flags copied from real to ovl inode */
 699 #define OVL_COPY_I_FLAGS_MASK   (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
 700 /* vfs inode flags read from overlay.protattr xattr to ovl inode */
 701 #define OVL_PROT_I_FLAGS_MASK   (S_APPEND | S_IMMUTABLE)
 702
 703 /*
 704  * fileattr flags copied from lower to upper inode on copy up.
 705  * We cannot copy up immutable/append-only flags, because that would prevent
 706  * linking temp inode to upper dir, so we store them in xattr instead.
 707  */
 708 #define OVL_COPY_FS_FLAGS_MASK  (FS_SYNC_FL | FS_NOATIME_FL)
 709 #define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
 710 #define OVL_PROT_FS_FLAGS_MASK  (FS_APPEND_FL | FS_IMMUTABLE_FL)
 711 #define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
 712
 713 void ovl_check_protattr(struct inode *inode, struct dentry *upper);
 714 int ovl_set_protattr(struct inode *inode, struct dentry *upper,
 715                       struct fileattr *fa);
 716
 717 static inline void ovl_copyflags(struct inode *from, struct inode *to)
 718 {
 719         unsigned int mask = OVL_COPY_I_FLAGS_MASK;
 720
 721         inode_set_flags(to, from->i_flags & mask, mask);
 722 }
 723
 724 /* dir.c */
 725 extern const struct inode_operations ovl_dir_inode_operations;
 726 int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir,
 727                              struct dentry *dentry);
 728 struct ovl_cattr {
 729         dev_t rdev;
 730         umode_t mode;
 731         const char *link;
 732         struct dentry *hardlink;
 733 };
 734
 735 #define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) })
 736
 737 int ovl_mkdir_real(struct ovl_fs *ofs, struct inode *dir,
 738                    struct dentry **newdentry, umode_t mode);
 739 struct dentry *ovl_create_real(struct ovl_fs *ofs,
 740                                struct inode *dir, struct dentry *newdentry,
 741                                struct ovl_cattr *attr);
 742 int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry);
 743 struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir);
 744 struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
 745                                struct ovl_cattr *attr);
 746
 747 /* file.c */
 748 extern const struct file_operations ovl_file_operations;
 749 int __init ovl_aio_request_cache_init(void);
 750 void ovl_aio_request_cache_destroy(void);
 751 int ovl_real_fileattr_get(const struct path *realpath, struct fileattr *fa);
 752 int ovl_real_fileattr_set(const struct path *realpath, struct fileattr *fa);
 753 int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
 754 int ovl_fileattr_set(struct mnt_idmap *idmap,
 755                      struct dentry *dentry, struct fileattr *fa);
 756
 757 /* copy_up.c */
 758 int ovl_copy_up(struct dentry *dentry);
 759 int ovl_copy_up_with_data(struct dentry *dentry);
 760 int ovl_maybe_copy_up(struct dentry *dentry, int flags);
 761 int ovl_copy_xattr(struct super_block *sb, const struct path *path, struct dentry *new);
 762 int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
 763 struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
 764                                   bool is_upper);
 765 int ovl_set_origin(struct ovl_fs *ofs, struct dentry *lower,
 766                    struct dentry *upper);
 767
 768 /* export.c */
 769 extern const struct export_operations ovl_export_operations;